Not Applicable.
The use of scanning interferometers is a common tool in the field of spectroscopy. By changing the path length of the arm(s) of the interferometer one can develop the Fourier spectrum of a light source and thus deduce it""s spectrum. In present systems, a mirror must be carefully moved back and forth some distance and yet must maintain very high levels of tolerance in the tilt for the scanning mirror. The classical method for removing tilt effects in the scanning mirror is to use a cube corner retroreflector as the scanning element. While this style of retroreflector does eliminate the effects of tilt it does so at the expense of size and mass of the scanning element, thus limiting the speed at which it can be moved.
Other systems have been devised that can remove the effects of tilt by using a Genzel style arrangement with a xe2x80x9croof topxe2x80x9d mirror. Such a system permits the scanning device to be much lighter than a cube corner retroreflector but does so at the expense of requiring either two beam-splitters or one that has a much larger area than found in an uncompensated system. There exists a need for an optical arrangement that automatically compensates for tilt of a light weight moving mirror.
The present invention provides an approach for removing the objectionable changes in the fringe pattern of the output of the interferometer system, normally caused by tilt in the scanning mirror, by carefully exploiting the nature of a Genzel arrangement of an interferometer, for example, to passively cancel the effects of tilt on the system.